Tart cherry juice induces apoptosis and cytotoxicity in MCF‐7 human breast cancer cells

Breast cancer is the most common non‐skin cancer in women and the fifth leading cause of death worldwide. Studies show that people with diets rich in fruits and vegetables have a reduced risk of chronic disease including some cancers. In this in vitro study, we tested whether tart cherry juice (TCJ) could alter the balance between cellular proliferation and cell death in MCF‐7 human breast cancer cells. TCJ was diluted into cell culture medium to 0.03–30% (v/v) and cells were incubated overnight with medium alone or increasing TCJ concentrations. Mitogenesis, measured by BrdU incorporation, was significantly reduced by 20% after both 10 and 30% (v/v) TCJ. MTT reduction, a mitochondrion‐dependent marker of proliferation and cytotoxicity, was significantly reduced by 27% and 80% at 10% and 30% TCJ, respectively. Apoptosis, measured by TUNEL, was increased up to 63% at TCJ concentrations ≥3%. However, programmed cell death was decreased (p<0.05) by 20% at 1% TCJ. DNA banding, or laddering, by agarose gel electrophoresis corroborated these results. Total cell numbers per flask were 8.03±0.8 and 8.04±1.5 × 10e6 for control and TCJ (1% v/v), respectively, and not significantly different. Viability by trypan blue exclusion was 96.8±2.2 and 97.4±0.3% (p>0.05) for control and TCJ (1% v/v). The results suggest that TCJ reduces cellular proliferation and induces cytotoxicity at higher TCJ concentrations (>10%) although apoptosis was induced at 3% TCJ. In contrast, protection against apoptosis was noted at 1% TCJ. This suggests that TCJ can be both protective and cytotoxic to cells depending on dose.